Gas-engine.



V s. I. PRESCOTT.

GAS ENGINE.

APPLICATION FILED APR.13,191Z. 1 1 142,034. Patented 001;. 20, 1914.

2 SEEETSSHEET 1.

J Invent??? S! I. PRE$GOTT.

GAS ENGINE.

ATLEOATION FILED APR.13,1912.

lnventi r of engine. and further providing feet cooling' of the UNITED STATES PKTENT SYDNEY I. rnnsoorr, or BROOKLYN, new roan, ASSIGNOB re ato-ronrnnx nears- MEN! COMPANY, OF NEW YORK, N.

GAS-ENGINE;

I in gas engines, particularly those of the two cycle three-port type.

One of the defects in engines of this type is due to the fact that al the burnt gas does not leave the cylinder at the end of the explosion stroke, or a part of the incoming fresh gas follows the burnt gas out of the zlyllil'iltl and is wasted.

it is one of the objects of the present invention to produce an engine of this type-in which eiliciency is increased over W118i, has been heretofore possible; at, by opening the ports more quickly so 1d, by producing an outflowing blast 1 air in the exhaust conduit to increase the vel ity of the exhaust, this blast stoppliig a... l a curtain air being formed adjacent thr 'haust port to prevent fresh gas from fiowi through the cylinder to the exha' rzst conduit.

A further defect in e gines of this type heretofore known is d e to the fact that the; are not balanced unless a plurality of cylinders is used and are not perfec balanced even then. It is often desir to use a single cylinder engine, and the elliciency of such engines, when unbalanced, is too low for economical operation.

Another object of the present invention is the production of a compact engine which is in perfect balance, whether a single cylinder or a plurality of cylinders is used thereby increasing the efficiency over what has been heretofore possible in a similar type engine speed but than is safe adapted to run not only at low also at speeds materially higher in an unbalanced engine.

Another serious defect of engines of this type'heretofore known is due to the impercylinder or cylinders, whether water or air is used for this purpose. lVhen water is used and circulated around the cylinders by a pump, in automobile engines for instance, it soon becomes warm, even reaching the steaming point i many cases. In such engines,

the cooling apparatus for the cylinder or cylinders is far from eifeclive. In the operation oi inany Specification of Letters Patent.

Application filed April 13,

conroeerron or new Patented oer. so, 1914.; 1812. Serial No. 690,553.

of the air cooled engines, a blast of air is driven against one side of the cylinder, and this is obviously imperfect as coolingagent, because it; does not equally cool all parts of the cylinder.

It is another object of the present invention to provide a simple air cooling apparatus which does or may include a part of the engine itself and in which cold air is caused to surround the cylinder or cylinders where the heatis generated vand is then driven out. to the atmosphere at high velocity, fresh cold air being sent through the air jacket surrounding the cylinder at every explosion.

lYith these inain objects, and other ob;-

invention consists in certainconstru'ctions and combinations which will be hereinafter fully described and then specifically set forth in the claims hereunto appended. i 3

In the accompanying drawings which form a part of this specificationand in which like characters of referenceindicate the same or like parts, Figure his alongitudinal sectional view of a device constructed in accordance with the invention, Fig. 2 is a longitudinal sectional view of the structure shown in Fi 4 l, the section being taken at right angles to the section in Fig. 1, Figs. 3, i, and 7 are respectively cross sect-ional views taken on the lines 3-3 -l, and '?F in Fig. 1, 5 is a sectional tons at the other end of the stroke, Fig. 6 is a longitudinal sectional view of a modification of the cylinder casting and cap shown in Fig. 1 said modification being for the purpose of illustrating the method of applying a water jacket to the cylinder, and Fig. 8 is a cross sectional view taken on the line 88 in Fi The device selector t.- illustrate the invention is a single-cylinder engine of the two-cycle three-poi" 'ype, and it is-to be understood that this particular engine is merely one of mar j possible concrete embodiments of the invention, and that the elements of the various combinations claimed may vary in construction within Wide limits.

is shown, there is provided a cylinder casting having an inner wall 1 forming an open end cylinder, and also having arr outer wall spaced from the cylinder 1. This casting for view similar to Fig, l, but showingthe pisher provided with a partition pressed and ignite by means to'be herein- I after described. This space therefore forms caused to return to their what may be termed an explosion chamber, marked 7 within the cylinder. It may be here remarked that the cylinder 1 does not perform the usual function of a gas engine cylinder, for the reason that the charge of gas is exploded between the pistons and there is no strain on the cylinder wall due to the explosion of the gas. In other words, the cylinder acts mainly as a guide or support for the istons. When a charge of gas is exploded etween the pistons, the piston heads travelin straight lines away from each other at equal speed, and then are initial positions. This reciprocatin the following mec ianismz There is provided a crank shaft 8 having oppositely disposed cranks 9' and 10-10. This crankshaft is mounted in suitable bearings, 11 carried by a casting 12, spaced from the cylinder cast-- ing by a hollow block 13. A rod 14 connects the crank 9 with a pin 1.5. journal'ed inside the inner piston before referred to. The

outer piston 5 is provided with a pair of outwardly projecting bosses 16 located near its lower end and diametrically opposite, and these bosses are connected with the cranks 1010 by means of rods 17-17 as clearly. shown in Fig. '2. The bosses 16 reciprocate within oppositely disposed slots 51 cut in the cylinder wall. It is to be understood that the weight of. the inner piston 1 with its'connecting rod 14 is equal to the weight of the outer piston 5 with its connecting rods 17-17. It will be therefore readily understood that, in the operation of the device, equal weights are always traveling in opposite directions at equal speed, that this results in perfect balance of the parts and engine as a whole, and that the engine, being in perfect balance, can be 3 .run at high speed if desired, and will run smoothly and quietly at all speeds. It will be further observed that the connections between the pistons and crank shaft are direct, and completely housed within the outer wall of the cylinder casting.

Located in-the wall of the cylinder 1, below the cooling chamber, is what may be termed an inlet chamber 18. This chamber is open to the 'nterior of the cylinder through a port 19. The inlet chamber 18 is further open to the outside of the outer wall the inner plston gas is introduced, 'com-' -walls of the two pistons.

motion is controlled by 20, and it is to be understood "that a carbureter, or a conduit leading from any other "suitable source of gas supply, may be mounted at the port 20;just described. It is obvious than any suitable carbureter may. be used in connection with the device, therefore none is shown.

- The space within the casting 12 and block 13 forms a crank chamber 21, and in this crank chamber the gas coming from the carbureter or other suitable source of supply is slightly compressed in the usual manner before it goes to the explosion chamber. ,Normally, however, the crank chamberis cut off from the inlet chamber by the provided with an inlet port 22, and the piston 6 is provided with, an inlet' port 23, these two ports being adapted to come into register with each other and with the inlet port 19 only at one end of the piston stroke;

and"

that is to say, when the piston" The piston 5 is' heads are closest together, as shown in Fig.

1. When these inlet ports are in register,

gas flows into the'interlor of the inner pischamber and therein compressed, it is transferred to the explosion chamber 7. To accomplish this end, there is provided an intake chamber 24, which is open to the crank chamber and which extends more than half way around the cyl'nder below the partition 3 before referred 0. course obvious that when gas is compressed in the gas chamber, it is also compressed in this intake chamber. The piston 5 is provided with a pair of intake ports 25 in its wall, these ports being diametrically opposed and being cirjcumferentially spaced ninety degrees'from the inlet ports 19, 22, and 23. The intake ports 25 are always "open to the intake chamber 24, irrespective of the position of the pistons. During the the stroke of the pistons,

greater part of however, these intake ports are. closed by the wall of the inner piston 6. This inner piston is provided, at a point just above its head, with ing formed by walls 27 projecting upwardly from the piston head and forming deflectors which'operate, the ports 25 come lntoregister with themtake chamber 24, to turn the two streams of gas flowing into the explosion chamber upward along the wall of the chamber toward the head of the outer piston 5 for the well n. 1 fter gas has been drawn into the crank It-is of intake ports 26, these ports be-' when the ports 26 and ton and the crank chamber to which it 'is known purpose of following the burnt gas 1 toward the exhaust port. The ports 25 and 26 come into register'with the intake chamber 2 1 when the piston heads are farthest apart, or in the position shown in Fig. 5, after which the gas flowing from the crank chamber into-the explosion chamber is compressed by the approaching movement of the piston heads, 3

For the purpose of igniting the com- 5 pressed charge in the explosion chamber, when the pistons are in the position shown in Figs. 1 or 2, or adjacent thereto, there is provided in the wall of the cylinder casting what maybe termed an ignition cham. her; This ignition chamber, marked 28, is adapted to receive any or other. igniting device not shown but which may be held therein by any suitable and. well known means. This igniting device will not roject inside the cylinder, but the ignition c amber 28 is open to the interior of the cylinder through the ignition port 29- formed in the cylinder wall. The outer piston 5 is provided with what may be 2p, termed an ignition port 30, and the inner piston 6 is provided with anignition port 31, these piston ignition ports being adapted to come into register with the ignition chamber only when the piston heads are close together. The piston 5 is further provided with piston rings 50 located on either side of its solutely prevent the firing of a charge at an any time other than the proper time. In the position shown in Figs. 1 and 2, the crank shaft connections are on a dead center. The ignition ports 30 and 31 are large enough to' permit. the cranks to move slightly ofl the dead center in either direction without closing the explosion chamber 7 to the ignition chamber 28. This allows for a slight advance or .retardation of the igniting device and it is obvious that when the device is timed to ignite the charge when the cranks are slightly off center in one direction, the crank shaft will rotate in one direction, and that whenthe device is timed to ignite the charge when the cranks are slightly off dead center in-the other direction the crank shaft will rotate in the opposite directions v A detailed description of the particular mechanism by means of which the ignition is effected is unnecessary to a full understanding of the present invention, and it is therefore neither illustrated nor described herein. Any suitably timed ignition mechanism may be used for this purpose.

Afterthe charge inthe explosion chamher is ignited and the pistons have moved apart under equal pressure and at equal speeds to the end of the expansion stroke,-

it is necessary to remove the burnt gas from the chamber. To accomplish this result, there is provided an exhaust ort 32 in the wall of the cylinder at the si e opposite the ignition chamber 28 and the inlet chamber 28. This exhaust port is normally closed .eb'to the explosion chamber 7. The outer pishaust ports are adapted to suitable spark plug cylinder is used. vThis exhaust port, or

ignition port 30. It will readily, be understood that this construction will abder exhaust port 32 the head ton-5 however is rev .ed with an exhaust a 7 d port 33, and the inner piston 6 is provided with an exhaust port at. These piston excome into register Wltllwbilfi cylinder exhaust port just before the intake ports 25 and 26 comeinto register with the intake chamber 24. This is for the purpose of starting the burnt gas out of the explosion chamber before the fresh gas flows in. Located in the outer wall 2 ofthe cylinder casting, directly opposite the cylinder exhaust port 32, is anexhaust conduit 35 leading to a suitable exhaust pipe, or manifold where more than one 8.0 manifold may be of any suitableconstruction and is not herein shown and described because it is not necessary for a full understanding of the present invention. It will be understood that the fresh gas flowing in through the intake ports will displace the outgoing burnt gas in the explosion chamber in a manner similar to that existing in any two-cycle engine, and it will be recognized that since'the piston other'at equal speed, said ports are opened quicker than the ports inan ordinary two cycle engine. This of course results in getting the burnt gas out of the explosion chamber quicker than has been heretofore possible.

For the purpose of further aiding the outflow of burnt gas and inflow of fresh gas, means are provided for producing a blast of air through the exhaust conduit 35 before the piston exhaust ports open to the cylinand the conduit 35, and this means may vary within widelimits. As shown, however, the exhaust conduit 35 is always open to the cooling chamber 4, but is only intermittently open to the explosion chamber 7. \Vhen the piston 5 travels upward, after the ignition of the charge in the chamber 7, the air in the cylinder 1 above of the piston 5 is forced into the cooling chamber 4 and blows out through the exhaust conduit 35.; This results in eliminating entirely the resistance of the atmosphere to the outflow of the burnt gas, and further results in increasing the veloc- 1'15 ityv of the outflow. Moreover, the velocity of the air forced through the cooling chamber decreases the temperature around and within the cylinder, and this permits of a higher degree of gas compression which in- 1 creases the power delivered without danger of premature explosion due to high temperature of the cylinder and piston as well as to the high temperature of compression.

4 When the piston 5 reaches its uppermost position, 7 this blast of air is automatically stopped, so that it is not in action when. the inflowing fresh gas has filled the explosion chamber. The upper end of the cylinder casting is closed by a cap 36 which is spaced ports approach each 90 v is drawn into i 41 of finewire mesh sible.

end of the cylinder 1 to permit a free flow of air from the interior of the cylinder to the cooling chamber. This cap carries a flexible disk valve 37 the move ment of which is limited by a curved plate 38 secured to the cap 86 by means of a rivet 39 or other suitable fastening device.

By an inspection of Fig. 3 it will be seen that a series of air ports 4:0 are provided which afford communication between the upper and lower part ofthe cap 36. For the purpose of preventing dust or other solid matter from passing through the air ports 40, the cap 36 is provided with an air strainer suitably secured to the upper part of the cap On the return stroke of the piston 5; that is to say, froin'the position shown in Fig. 5 to the position shown in Fig. 1, a partial vacuum is produced in the upper part of the cylinder 1. This results in flexing the valve 37 and-opening the air ports 410 through which air flows to fill the upper part of the cylinder. Although the air jacket is always open to the exhaust port 35, the downwardly moving piston 5 does not draw burnt gas back from the exhaust ripe to the cooling chamber because the momentum due to the high velocity'of the outgoing gas constitutes a resistance to its travel in the opposite direction; that is, back to the cooling chamber, which resistance is far in excess of the very slight resistance of the readily flexible valve 37, especially since the outgoing gas rushing through the exhaust pipe after the blowing action has ceased sets up in the cooling chamber an ejecting action which in itself tends to open' the valve 37. It will be readily understood, therefore, that during each reciprocation of the piston, cold air the cylinder and is forced through the air jacket or cooling chamber a. Since the cooling chamber surrounds the expansion chamber even when the pistons are farthest apart, and since the cylinder itself is not subject of direct heat, it follows that a lower degree of temperature will be maintained than has been heretofore posfrom the upper It will be readily understood that the construction just described constitutes an air pump performing two distinct functions; first, to cool the engine, and second, to aid the exhaust. Furthermore, it is, apparent that the greater the speed of the motor, the greater speed of "the pump will be, and the more cold air-will be driven through the cooling chamber.

It is apparent that since the efiective area of the two-pistons is equal, and since the weight of the two pistons with their respective connections is also equal, the downward thrust on the crank 9 will equal thrust on the cranks 10-l0. T his results in materially reducing the pressure upon the jacket 18 desired, the only 1S inthe form of 'rounding the upper end shaft, operating bearings 11, and thereby upon said bearings.

It is believed to be unnecessary to use a water jacket for cooling purposes 'inf any engine of this type. If, however, a water change necessary I the cylinder cap for the same. Referring particularly to Figs. 6 and 8, the cylinder casting is provided with a partition 42, whicl i separates the space between the cylinder 1 and the outer reduces the wear casting and wall 2 into a cooling chamber d3 nearly sur-- of the cylinder, and further forming well 44 down one side of the cylinder. The casting is further pro-, vided with bosses andti to which "water" circulating ing is further provided w'th vertical-walls 47, 4-17, which with a portion of the cylinder 1 and outer wall 2 form a channel 4E8 ex: tending from the space above the top of the cylinder to the exhaust conduit 35. A cap a9 is provided and shaped to close the upper end ofthe cooling chamber l3, but which keeps the interior of the cylinder in open communication with "the air ehannelf l8.

in view of the foregoing, a detailed descriptionof the operation of p deemed unnecessary and is therefore omitted in the interest of brevity,

Changes and variations may be made in the structure by means of which the invention is carried into effect. 'flhe invention, therefore, is not to be restricted to themecise details of the structure shown and described. Furthermore, certain parts of the invention are capable of use independent of other parts, and such independent use is contemplated. 1

What is claimed is: p

1. In a gas engine, the combination with a support, of a pair of power pistons concentrically mounted in the support, a crank shaft, operating connections between the pistons and crank shaft, an exhaust conduit intermittently open to the space between the pistons, and means cooperating with the con-' duit for producing a blast of air through said conduit to the atmosphere during the power stroke.

2. In a gas engine, support, of a pair of power pistons concentrically mounted in the support, a crank .connections between the pistons and crank shaft, an exhaust conduit intermittently open to the space between the pistons, and intermittently operating means coiiperating with the conduit for producing a blast of air through the conduit-to the at mos-phere before the conduit. cpenskduring the power stroke, said means being timed to go out of action before the conduit closes to the upward the space between the pistons.

3. In a gas engine, the combination with a sun ort. of a ',air of ower istons concenthe combination with a the device 1s duit intermittently open to the initt'ently open to; the space het tricallv mounted in thesunocrt. crank e ii 1 I, shatt, operating connections between the pistons and crank shaft, an exhaust conduit intermittently open to the space between the pistons,- and meanscooperating with the conduit for prod cing a hlast oi: air through said conduit to the atmosphere before the conduit opens, said means including one of the power pistons operating as an pls 4c. Ina gas engine, the combination a cylinder, of a pair of'power pistons concentrically mounted 1 within the cylinder, a crank shaft; operating connections between the pistons and crank shaft, an exhaust race so tween the pistons, and means cotipera-ting with-the conduit to producing a blast. of air through said conduit the atmosphere dur ing the power stroke.

5. In a gas engine, the combination with a cylinder having an ignition chamber in its wall, of a pair or" power pistons concentrically mounted within the cylinder and each having an ignition port in adaptedto open the space between tons to the ignition chamber, a cran operating connections between the pistons and crank shaft-,nn exhaust conduit intermittently open to the sp: re between the pistons, and means cooperating with the conduit for producing a. blast of air through said conduit to the atmosphere during the power stroke.

6. In a gas engine, the combination with a cylinder having-an ignition chamber in its well, of an inner and an outer piston concentrically mounted within the c each. having an ignition port in adapted to open the space between tons to the ignition cllalllli piston rings carried by the outer piston .;n both sides of its ignition port, a crank shaft, operating connections between the pistons crank shaft, an exhaust conduit intermitten ly opentot-he space between the pistons, and means cooperatin with the conduit for producing-a blast or air through said conduit to the atmosphere during the power stroke.

7. In a gas engine, the combination with a. cylinder llSiV-ll'lg' an ignition. chamber in its Wall, of a pair of power pi. ns concentrically mounted within the cylinder each havinganignition port in its wall adapted to open't-he' space between the, pistons to the ignitionchajmher, said ports being timed to register with theignition chamber only at one end of the piston stroke, a crank shaft, operating connections between the pistons and crank shaft, an exhaust c iuit interenthe pistons, and means coiiperating with. the conduit for producing a blast of airthrough said conduit to the atmosphere during the power stroke.

8. In a gasengine, the comhinatior with .5 A 13 snail,

having an .inteke chambe'r in its mounted within the cylinder each trically mounted within the cylinder each having an int; he port its well adapted to open the space between the pistons to the intake cheznher, seid ports being timed to register with the intake chamber only at one end of the piSifOIl stroke, a crankshaft, open sting connections between the pistons and crank shaft, an exhaust conduit intermittently open to the space between the pistons, and means cooperating the conduit producing a blast of air tn: ugh said conduit to the atmosphere during the power stroke.

10. In a gas engine, the combination with a cylinder having an exhaust port its wall, of a pair of power pistons concentrically mounted within the cylinder each having an exhaust port in'its wall adapted to open -thespace between thepistons-tothe cylinder er;- haust port, a crank shaft, operating con: nections between the pistons and crankshaft, an exhaust. conduit intermittently open through the cylinder exhaust port to the space between the pistons, and means cooperating :with': the conduit for producing a blast or. .-ir through said conduit to the at mosoherebefore the conduit opens.

ii. In a gas engine, the combination with a cylinderhefiing an exhaustport in its Wall, of a pair of power pistons concentrically mountedwithin-thecylinder each having an exhaust port in its well adapted'to open the space between the pistonstoithe cylinder exhaust port, ports heingtimed to register with the cylinder exhaust port before the pistons reach the end of their expansion stroke, crank 'sha'fi,operating-connections between-the istonsand crank shaft an ere I haust conduit intermittently open to the space betweenthe pistons, and means'coopcrating 'w;

mosphcre before the conduit opens.

the conduit for. producing .a blast ofair through said conduit to the at- 12. In a gas engine, the combination with i a crank chamber, of a. cylinder having a gas inlet chamber in its wal, pair-0f power pistons:concentrically mounted within the cylinder each having a gas inlet port inits wall adapted to open the inlet chamber-to the crank chamber, means for transferring,

' mounted within the cylinder eachhaving a exhaust port and an ignition chamber in its said conduit to the atmosphere before the inlet ch amber to chamber to the space between 1 ie pistons, said gas inlet ports and said ignition ports being timed to register only when the piston heads are closest together and said intake ports being timed to register only when the piston heads are farthest apart and said exhaust ports being timed to register just before the intake ports register, a crank shaft, operating connections between the pistons and crank shaft, an exhaust conduit open to the exhaust port of the cylinder, and means cooperating with the conduit for producing a blast of air through said conduit to the atmosphere before the piston exhaust ports gas from the crank chamber to the space between the pistons, a crank shaft, operating connections between the pistons and crank shaft, an exhaust conduit intermittently open to the space between the pistons, and means cooperating with the conduit for producing a blast of air throughvsaid conduit to the atmosphere before the-condu t opens.

13, In a gas engine, the combinationwith a crank chamber, of a cylinder having a gas inlet chamber in its wall, a pair of power pistons concentrically mounted within the cylinder each having a gas inlet port in its wall adapted to open the inlet chamber to thecrank chamber said ports being timed to open to the cylinder exhaust port and the register with the gas inlet chamber only at conduit.

16. In a gas engine, the combination with a crank chamber, of a cylinder having a gas inlet chamber and an ignition chamber in one of its wall and an exhaust port in the opposite side hambers one at either side of the cylpositioned ninety degrees l port and open to 1 channel, apair of power pi trically mounted within the cyl' '7 having an inlet'port in its wall at. open the inlet chamber to the crank cnaicbe and each having a pair of intake ports in its wall adapted to open the intake chambers to the space between the pistons and each having an exhaust port inits wall adapted to open the sp' 1e between the pistons to the cylinder exhaao pert each having an ignition port in wall adapted to open the chamber to the space between the a crank shaft and operating conand crank shaft. a gas engine, 1e combination with amber, of a cylinder having a gas inlet chamber and an'ignition chamber in one side of its'wall and an exhaust port in the opposite side of its wall and a' pair of intake chambers one at either side of the cylinder and both positioned ninety degrees from the exhaust port, a pair of power pistons concentrically mounted within the cylinder each having an inlet port in its wall adapted to open the inlet chamber to the crank chamber'and each having a pair of intake ports in its wall adapted to open the intake chambers to the space between the pistons and each having its wall. adapted to open the space between the pistons to the cylinder exhaust port and each having an ignition port in its wall adapted to open the ignition chamberto the space between the pistons, a crank shaft,

one end of the piston stroke, means for transferring gas from the crank chamber to the space between the pistons, a crank shaft, operating connections between the pistons and crank shaft, an exliaaustcon uit intermittently open to the space between thepistake c tons, and means cooperating with the conir r both: duit for, producing a blast of air through conduit opens.

14:, In-a gas engine,"the combination with a crank chamber, of a cylinder having a gas inlet chamber and an intake chamber and an exhaust port and an ignition chamber in its wall, a pair of power pistons concentrically gas inlet port in its wall adapted the crank chamber and intake portin its wall space between the pistons and to open the i the intake char her to the l i l each having an adapted to open each having an exhaust port in its wall adapted to open the space between the pistons to the cylinder exhaust port and each having'an ignition port in its wall 'a dapted to open the ignition chamber to the space between the pistons, a crank shaft, operating connections between thepistons and crank shaft, an exhaust conduit open to the exhaust port of the cylinder, and means cooperating with the conduit for producing a blast of air through said conduit to the atmosphere before the piston exhaust ports open to the cylinder exhaust port and the conduit.

15. In a gas engine, the combination with a crank chamber, of a cylinder having a gas inlet chamber and an intake chamber and an wall, a pair of power pistons concentrically mounted within the cylinder each having a gas inlet port in its wall adapted to open the inlet chamber to the crank chamber and each having an intake port in its wall adapted to open the intake chamber to the space between the pistons and each having an exhaust port in its wall adapted to open as space between the pistons to the cylinder exhaust port andeach having an ignition port in its wall adapted to open the ignition an exhaust conduit interand crank shaft,

cylmder and mittently open through the piston exhaust ports. to the space between the pistons, and means cooperating with the conduit for producing a blast of air through said conduit to the atmosphere before the of its wall and a pair of man exhaust port in operating connections between the pistons mince;

piston and cylinder exhaust ports open to duit intermittently open to the chamber, and

located adjacent intermittently operating means cooperating with the conduit for producing a blast of air through said conduit to the atmosphere, said means being timed to come into operation during the power stroke only and before the conduit opens to the chamber and to stop before the conduit closesto the chamber.

20. In a gas engine, the combination with an open end cylinder, of an explosion chamber within the cylinder, an exhaust conduit intermittently open to the chamber, and an air pump including the open end of the cylinder and a reciprocating piston within the cylinder and a flexible disk air inlet valve the end of the cylinder, said pump cooperating with the conduit for producing a blast of air through said conduit o the atmosphere before the conduit opens.

:31. In a gas engine, the combination with an open end cylinder, or an explosion chamber within the cylinder, an exhaust conduit intermittently open to the chamber, and an ai pump including the open end of the cylin c: and a reciprocating piston within the cylinder and ai fienible disk air inlet valve located adjacent the end. or" the cylinder and an air jacket inclosing one end oi the cyl inder, said pump cooperating with the conduit for producing a. blast of air through said conduit to the atmosphere before the conduit opens.

22. In a gas engine, the combination with an open end cylinder, of explosion chamber within the cylinder, an exhaust conduit intermittently open to the chamber, and an air pump including a reciprocating power pistoncne side of which acts as an air piston within the open end of the cylinder and a flexible disk air inlet valve located adja cent the end of the cylinder and an air jacket inclosing one end oi the cylinder, said pump cooperating with the conduit for producing a blast of air through said conduit to the atmosphere before the conduit opens.

23. In a gas engine, the combination with an open end cylinder, of an explosion chamber within the cylinder, an exhaust conduit intermittently open to the chamber, and an air pump including a reciprocating power piston one side of which acts as an air piston within the open end of the cylinder and and means cooperata flexible disk air inlet valve andan air strainer located adjacent the end of the cylinder and an air jacket inclosing one end of the cylinder, said pump cooperating with the conduit for producing a blast of air through said conduit to the atmosphere'before the j conduit opens.

at. In a gas engine, the combination with I an open end cylinder, of an explosion chamber within the cylinder, an exhaust conduit intermittently open to the chamber, and'an air pump including a reciprocating power piston one side or" which acts as an air piston within the open end of the cylinder and flexible disk air inlet valve and an air ;strainer both. carriedby a cap spaced from fthe upper end of the cylinder and an air jacket inclosing one end of the cylinder, said pump cotiperating with the conduit jior producing a blast of air through said conduit to the atmosphere before the conduit opens.

25. In a gas engine, the combination with a cylinder having an ignition chamber in its wall, or" a pair of power pistons concenhau lg an ignition port in its wall adapted to open the ignition chamber to the space between the pistons, a crank shaft, and operating connections between the pistons and crank shaft.

26. In a gas engine, the combination with a cylinder having an ignition chamber in its wall, or a pair or" power pistons concentrically mounted within the cylinder each having an ignition port in its wall adapted to open the ignition chamber to the space between the pistons, said ports being timed to register with the ignition chamber only at one end of the piston stroke, a crank shaft, and operating connections between the pistons and crank shaft.

27. In a gas engine, the combination with a cylinder having an intake chamber in its wall, of a pair of power pistons concentrically mounted within the cylinder each having an intake port in its wall adapted to open the intake chamber to the space between the pistons, a crank shaft, and operating connections between the pistons crank shaft.

28. In a gas engine, the combination with a cylinder having an intake chamber in its well, of a pair of power pistons concentrically mounted within the cylinder each having an intake port in its wall adapted to open the intake chamber to the space between the pistons, said ports being timed to register with the intake chamber only at one end of the piston stroke, a crank shaft, and operating connections between the pistons and crank shaft.

29. in a gas engine, the combination with a cylinder having an exhaust port in its wall, or a pair of power pistons concentritrically mounted within the cylinder each cally mounted within the cylinder each having an exhaust port in its wall adapted to open the cylinder exhaust port to the space between the pistons, a crank shaft, and operating connections between the pistons and crank shaft.

30. In a gas engine, the combination with a cylinder having an exhaust port in its wall, of a pair of power pistons concentrically mounted within the cylinder each having an exhaust port in its wall adapted to open the space between the pistons to the cylinder exhaust port said piston ports being timed to register with the cylinder port just before the pistons reach the end of their expansion stroke, a crank shaft, and oper-- ating connections between. the pistons and crank shaft.

31. In a gas engine, the combination with a'crank chamber, of a cylinder having a gas inlet chamber in its wall of a pair of power pistons concentrically mounted within the cylinder each having a gas inlet port in its wall adapted to open the inlet chamber to the crank member, a crank shaft, and operating connections between the pistons and crank shaft.

32. In agas engine, the combination with a crank chamber, of a cylinder having agas inlet chamber in its wall, a pair of power pistons concentrically mounted. within the cylinder each having a. gas inlet port in its wall adapted to open the'inlet chamber to the crank chamber, said ports being timed to register with the inlet chamber only at one end oi the piston stroke, a crank shaft, and operating connections and crank shaft.

In a gas engine, the combination with a crank chamber, oi a cyl' ler having a gas inlet chamber and an intake chamber and an exhaust port and an ignition chamber in its wall the intake chamber being open to the crank chamber, a pair of power pistons concentrically cylinder each having a gas inlet port in its wall adapted to open the inlet chamber to the crank chamber and each having an intake port in its wall adapted to open the intake chamber to the space between the pistons and each having an exhaust port in its wall adapted to open the space between the pistons to the cylinder exhaust port and each having an ignition port in its wall adapted to open the ignitipn chamber to the space between the pistons, a crank shaft, and operating connections between the pistons and crank shaft.

84:. In a gas engine, the combination with a crank chamber, of a cylinder having a gas inlet chamber and an intake chamber and an exhaust port and an ignition chamber in its wall the intake chamber being open to the crank chamber, a pair of power pistons con centrically mounted within the cylinder between the pistons mounted within the each having a gas inlet, port ir its wall adapted to open the inlet chanzcser to the crank chamber and each having an intake port in its wall adapted to open the intake chamber to the space between the pistons and-each having an exhaust port in its wall adapted to open the space between the pistons to the cylinder exhaust port and each having an ignition port in its wall adapted to open the ignition chamber to the space between the pistons, said gas inletports and saidignition ports being timed to register only when the piston heads are closest together and said intake ports being timed to register only when the piston heads are farthest apart and said exhaust ports being timed to register just before the intake ports register, a crank shaft, and operating con nections between the pistons and crank shaft.

35. In a gas engine, the combination with a casting having an inner wall forming a cylinder open at both ends and having an outer wall spaced rrom the cylinder and having a transverse partition dividing the space between the walls to form a cooling chamber open into one end of the cylinder, of a 'pairof power pistons concentrically mounted within the cylinder opposite the cooling'chamber, a crank shaft, and operating connections between the. pistons and crank shaft.

36. In a gas engine, the combination with a casting having an inner wall forming a cylinder open at both ends and having an outer wall spaced from the cylinder and having a transverse partition dividing the space between the walls to form a cooling chamber at one end of the cylinder,,of an ignition chamber and a gas inlet port spaced apart and located at one side of the cylinder, a pair of intake ports and an exhaust port located in the cylinder wall and circumferentially spaced from each other and from the ignition chamber and gas inlet port, a pair of power pistons concentrically mounted within the cylinder opposite the cooling chamber and each provided with an ignition, intake and exhaust port adapted to respectively register with the ignition and intake chambers and exhaust port of the cylinder, a crank shaft, and operating connections between the -pistons and crank shaft.

37. In a .gas engine, the combination with a casting having cylinder open at both ends and having an outer wall spaced. from the cylinder and. having a transverse partition dividing the space between the walls to form a cooling chamber at one end of the cylinder, of a pair of power pistons concentrically mountcd within the cylinder opposite the cooling chamber, a crank shaft, operating connections between the pistons and crank shaft an exhaust conduit intermittently open to l the space between the pistons, and means an inner wall forming a apart and located at one side of the cylinder,

a pair of intake ports and an exhaust port located in the cylinder wall and circumfeu entially spaced from each other and from the ignition chamber and gas inlet port, a pair of power pistons concentrically mounted withinthe cylinder opposite the cooling chamber and each provided with an ignition, intake and exhaust port adapted to respectively register with the ignition chamber, intake and exhaust ports of the cylinder, a crank shaft, operating connections between the pistons and crank shaft, an exhaust conduit intermittently open to the space between the pistons, andmeans cooperating with the conduit for producing a blast of air through said conduit to the atmosphere before the conduit opens, said means including one of the power pistons operating as anair piston.

39. In a gas engine, the combination with a support, of a pair of power pistons concentrically mounted in the support, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight, an exhaust conduit intermittently open to the space between the'pistons, and means cooperating with the conduit for producing a blast of air through said conduit to the atmosphere during the power stroke.

40. In a gas engine, the combination with a support, of a pair of )WGF pistons concentrically mounted in the support, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight, an exhaust conduit intermittently open to the space between the pistons and intermittently operating means cooperating with the conduit for producing a blast of air through the conduit to the atmosphere during the power stroke, said means being timed to go out of action before the conduitcloses to the space between the pistons. Q

1. In a engine, the combination with a cylinder having an ignition chamber in its wall, of a pair of power pistons concentrically mounted within the cylinder each having an ignition port in its wall adapted to open the ignition chamber to the space between the pistons, a crankshaft having oppositely disposed cranks,- rods directly connecting the pistons and cranks,

equal weight.

42. In a gas engine, the combination with a cylinder having an ignition chamber in its wall, of a pair of power pistons concentrically mounted within the cylinder each having an ignition port in its wall adapted to open the ignition chamber to the space between the pistons, said ports being timed to register with the ignition chamber only at one end of the piston stroke, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight.

43. In agas engine,the combination with a cylinder'havingan intake chamber in its wall, of a pair of power pistons concentrically mounted within the cylinder each havsaid pis- 1 tons with their respective rods being of ing an intake port in its wall adapted to open the intake chamber to the space be tween the pistons, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight.

4A. In a gas engine, the combination with a cylinder 'havingan intake chamber in its wall, of a pair of power pistons concentrically mounted within the cylinder each having an intake port in its wall adapted to open the intake chamber to the space between the pistons, said ports being timed to register with the intake chamber only at one end of the piston stroke, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being 'of equal weight.

45. In a gas engine, the combination with a cylinder havin an exhaust port in its wall, of a pair 0 power pistons concentrically mounted within the cylinder each having an exhaust port in its wall adapted to open the cylinder exhaust port to the space between the pistons, .a crank shaft having oppositely disposed cranks, rods directly connecting the. pistons and cranks, said pistons with their respective rods being of;

equal weight.

46. In a gasengin'e, the combination with a cylinder having an exhaust port in its wall, of apair of power pistons concentri cally mounted within the cylinder each hav ing' an exhaust port in its wall adapted to open the space between the pistons to the cylinder exhaust port said piston ports being timed to register with the cylinder pot just before the pistons reach the end of their expansion stroke, a crank shaft having op-,

positely disposed cranks, rods directly conwall ad'aptcduto open the inlet chamber to he crank chamber, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons I with their respective rods being of equal :the crank chamber and take port in its wall adapted to open the the pistons in a gas engine, the combination with 'ci -k chamber, of a cylinder having a gas inlet chamber in its wall, a pair of power pistons concentr cally mounted within the cylinder each having a gas inlet portiii its wail adapted to open the inlet chamber to the crank'chamber, said port's being timed register with the inlet chamber only at one end of the piston stroke, a crank shaft having oppositely disposed cranks, rods directly connecting the piste?" and cranks, said p'istons'with their respec rods being of equal weight.

4-9. In a gas engine, the combination with a crank chamber, of a c, 'nder hving a gas inlet chamber and intake Camber and an exhaust port and an ignition chamber in its wall the intake chamber being to the crank chamber, a pair of power pistons concentrically mounted w cylinder having a gas inlet po t in its walladapi to cpen the inlet cl: t each havin inintake chamber to the space between. the pistonsand each having an exhaust port in its wall adapted to open the space between to the cylinder exhaust port and ignition port in its wall ada'tlted to open the ignition chamber to the space between the pistons, a crank shaft having oppositelydisposed cranks, rods directly connecting the pistons and cranks.

each having an i said pistons'with their respective rods being of equal weight.

.50. In a gas engine, the combination with a crank chamber, of a cylinder having a gas inlet chamber and an intake chamber and an ignition chamber in its wall the intake chamber using open to t e crank chamber, a pair of power pistons concentrically mounted within the cylinder each having a gas inlet port in its wall adapted to open the inlet chamber to the crank liamber and each having an intake port in its wall adapted icopen the intake chamber to the space between the pistons and each having an exhaust port in its wall adapted to open the space between the pistonsto the cylinder exhaust port and each having an ignition.

an exhaustlp ort and of a cylinderhaving a gas l l l l i l l l l 1 i l l l l 1 port in its wall adapted operating with the conduit to open the ignition chamber to the space between the pistons, said gas inlet ports and said'ignition ports being timed to register only when the piston heads are closest together and said intake ports being timed to register only when the piston heads are farthest apart and said exhaust ports being timed to register just before the intake ports register, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistonsfwith their respective rods being of equal weight.

51. In a gas engine, the combination with a casting having an inner wall forming a cylinder. open at both ends and having an outer wall spaced from the cylinder and having a transverse partition dividing the space between the walls to form a cooling chamber open into one end of the cylinder, of a pair of power pistons concentrically mounted within the cylinder opposite the cooling chamber, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight. 4

52. In a gas engine, the combination with a casting having an inner wall forming a cylinder open at both ends and having an outer wall spaced from the cylinder and having a transverse partition dividing the space between the walls to form a cooling chamber at one end of the cylinder, of an ignition chamber and a gas inlet port spaced apart and located at one side of the cylinder, a pair of intake ports and an exhaust port located in the cylinder wall and circumfercntially spaced from each other and from the ignition chamber and gas inlet port, a pair of power pistons concentrically mounted within the cylinder opposite the cooling chamber and each providedwith an ignition, intake and exhaust port adapted to respectively register with the ignition and intake chambers and exhaust port of the cylinder, a crank shaft, having oppositely disposed cranks, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight.

In a gas engine, the combination with a casting having an inner wall formingua cylinder open at both ends and having an outer wall spaced from the cylinder and having a transverse partition dividing the space between the walls to form a cooling chamber at one end of the cylinder, of a pair of power pistons concentrically mounted within the cylinder opposite the cooling chamber, a crank shaft having oppositely disposed cranks, rods directly connecting the pistons and cran is, said pistons with their respective rods being of equal weight, an exhaust conduit intermittently open to the space between the pistons, and means cofor producing a blast of air through said conduit to the atmosphere before the conduit opens, said means including one of the power pistons operating as an air piston.

In a gas engine, the combination with a casting having an inner wall forming a cylinder open at both ends and having an outer wall spaced from the cylinder and having a transverse partition dividing the space between the walls to form a cooling chamber at one end of the cylinder, an ignition chamber and a gas inlet port spaced apart and located at one side of the cylinder, a pair of intake ports and an exhaust port located in the cylinder wall" and circumferentially spaced from each other and from the ignition chamber and gas inlet port, a

pair of power pistons concentrically mount-- ed within the cylinder opposite the cooling chamber and each provided with an ignition, intake and exhaust port adapted to respectively register with the ignition chamber, intake and exhaust port of the cylinder, a or ask shaft having oppositely disposed cran (s, rods directly connecting the pistons and cranks, said pistons with their respective rods being of equal weight, an ex haust conduit intermittently open to the space between thepistons, and means cooperating with the conduit for producing a blast of air through said conduit to the atmosphere before the conduit opens, said means including one ofthe power pistons operating with operating as an air piston.

In a gas engine, the combination with a cylinder, of an exhaust pipe a cooling chamber outside said cylinder and having an outlet through the exhaust pipe to the atmosphere, and means cooperating with the chamber for producing a blast of air through said chamber to the atmosphere only during the power stroke.

56-111 a gas engine, the combination with a cylinder, of an exhaust pipe a cooling chamber outside said cylinder and having an outlet to the exhaust pipe and means including a piston within the cylinder co the chamber for producing a blast of air through said chamber and exhaust pipe to the atmosphere only during the power stroke.

57. In a gas engine, the combination with an open end cylinder, of an exhaust pipe a cooling chamber outside of and in open communication with the cylinder and having an outlet to the exhaust pipe, and an air pump cooperating with the chamber for producing a blast oi air through said chamber and exhaust p'pe to the atmosphere only during the power stroke, said pump including a power piston within the cylinder one side of which acts as an air piston.

58. In a as engine, the combination with an open en cylinder, of an exhaust pipe a cooling chamber outside of and in open communication with the cylinder and having an outlet to the exhaust pipe, and an air pump cooperating with the chamber for producing a blast of air through said chamber and exhaust pipe to the atmosphere only during the power stroke, said pump including an inlet valve adjacent'the open end of the cylinder and including a power piston within the cylinder one side of which acts as an air piston.

59. In a gas engine, the combination with a cylinder, of a cooling chamber associated with the cylinder, an exhaust pipe and an air pump cooperating with the chamber and exhaust p' only during the power stroke.

60. In a gas engine, the combination with a cylinder, of a cooling chamber surrounding the cylinder, an exhaust pipe and an air. pump cooperating with the chamber an exhaust pipe to drive cold air therethrough only during the power stroke.

61. In a gas engine, the combination with a cylinder, of a cooling chamber associated with the cylinder, an exhaust pipe and an air pump cooperating with the chamber and exhaust pipe to drive cold air therethrough only during the power stroke, said air pump including a piston operatlng 1n the cylinder. Y

62. In a gas engine, the combination with a cylinder ofa cooling chamber surrounding the cylinder, an exhaust pipe and an air pump cooperating with the chamber and exhaust pipe to drive cold air therethrough only during the power stroke, said air pump including a piston operating in the cylinder.

63. The combination with a gas engine having an internal cooling chamber, of an exhaust pipe and an air pump coiiperating with the chamber and exhaust pipe to drive cold air therethrough only during the power stroke, said engine and said pump having a moving member in common.

In testimony whereof, I have signed my name to this specification in'the presence of two subscribing witnesses.

SYDNEY I. PRESCOTT. Witnesses:

FRANK H. VIoK, Jr., JAMES A. MOCANN.

pe to drive cold air therethrough 

